Pristella Tetra. Shy small tetra who don’t bother guppies. A very hardy fish and is better to have it in a group of six if they are the only tetras in a 30 to 10 gallon fish tank in my opinion . I never had a problem with them as long as I did water changes weekly.
Glowlight Tetra. Smaller than pristella and thin bullet shape. Had no problems with them neither. They too have to be in a group of six at least
Black Neon Tetra. I like the looks of them. Appearance is thicker bullet shape than glowlights. No issues with them neither.
Diamond Tetra. I have six of them. None of them died. I have them in a 60 gallon fish tank with angelfish and plecos.
Black Phantom Tetra. I got 2 females and 1 male. Two died in 48 hours, and I don’t know still why.